I wouldn't want to do this place with a group in full columi. You'll have a terrible time.

If a player cannot understand and complete at least some fights in HM KP/ HM EV, they won't fare well in EC Story Mode.

This. If you can clear HM's without difficulty then you're ready for SM Denova. Full columni means everyone has to really be top of their game - you should have people with crafted/farmed Rakata pieces and some people full or near full Rakata just from running hard modes. There's a number of burst/DPS checks in the operation that will be hard to beat unless your raid is at least partially Rakata such as the bombers on Kephess.

I also agree with the guy above that the mechanics in this operation are stupid in the sense that they are counter-intuitive (rail shot, person furthest away has no reason for it and is invisible as an example) and don't really make sense or have visible/audible indications. You learn the fights by reading about it and memorizing how it works and its kinda dumb in that regard. I much prefer mechanics like on Lost Island's Lorrick that are visible but still challenging.